The overall goal of this project is an in-depth analysis of the thymus-derived lymphocyte and its products. The basic approach is to use continuously propagable T-cell lines which express specificity for individual antigens. Highly purified, functionally characterized, antigen-sensitized T-cells have been fused with extensively analyzed, cloned T-cell lymphomas to make T cell hybrids. In other experiments, purified T cells have been treated with antigen and T-cell growth factor. Such antigen-specific continuous T-cell lines are being used to analyze the parameters which regulate T-cell recognition of antigen and as source material for lymphokines. Several lines and clones have been developed which produce lymphotoxin, interferon, migration-inhibitory factor and/or interleukin-2 either constitutively or after induction with antigen or mitogen. Regulation of such lymphokine production in T-cell clones and hybrids will be studied. The effect of alteration of growth parameters and addition of antigen-specific suppressor factors will be analyzed. Isolation and analysis of mRNA for antigen-specific molecules and lymphokines will be accomplished by enrichment of polyadenylated RNA and by immunoprecipitation of polysomes containing the mRNAs of interest.